Connecting arrangement between a shaft journal and a joint part

ABSTRACT

A connecting arrangement between a shaft journal ( 2 ), which is mounted so as to be axially fixed with respect to a unit, and a joint part ( 10 ) which can be pivotably attached to the shaft journal in a rotationally fixed manner. A shaft nut ( 5 ) having an internal thread ( 6 ) which can be screwed onto an external thread ( 4 ) of the shaft journal, is provided with an additional external thread ( 8 ) onto which a further nut ( 12 ) can be screwed via a counter-thread ( 21 ) to produce an axially acting interlocking connection ( 13 ) between the further nut ( 12 ) and the joint part ( 10 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international patent applicationno. PCT/DE2007/001465, filed Aug. 17, 2007 designating the United Statesof America, and published in German on Feb. 28, 2008 as WO 2008/022625,the entire disclosure of which is incorporated herein by reference.Priority is claimed based on Federal Republic of Germany patentapplication no. DE 10 2006 039 575.1, filed Aug. 23, 2006.

BACKGROUND OF THE INVENTION

The present invention relates to a connecting arrangement between ashaft journal, such as the shaft journal of a transmission shaft inparticular, and a joint part, such as the joint inner part of aconstant-velocity fixed joint for a motor vehicle.

Such connecting arrangements are known from EP 1 519 063 A2 and US2008/0107477 (=WO 2006/037389).

In an embodiment according to EP 1 519 063, a shaft nut is screwed ontoa shaft journal, which forms the end of a transmission input shaft of arear axle transmission, on which a clamping nut is provided so it isrotatable toward the shaft nut via a form-locking connection in theaxial direction. Such transmissions are provided to the vehiclemanufacturer as a pre-assembled unit having a shaft nut and a clampingnut seated loosely thereon. Before the shipping, the transmission itselfmust be balanced as a unit. The clamping nut mounted loosely on theshaft nut interferes with this. However, this interferes not only duringthe balancing, but rather also interferes with the noise testing of thetransmission. The nut must therefore be fixed in some way for balancingand for the noise testing.

US 2008/0107477 discloses an embodiment of a connection between a shaftjournal of a transmission and a constant-velocity rotary joint having aconfiguration in which a threaded sleeve, which may be screwed onto theshaft journal, is connected via a non-detachable connection to the jointinner part of a constant-velocity joint. In another illustrativeembodiment, an intermediate sleeve is also used, which is welded to thejoint inner part. A further embodiment variant also discloses a nutwhich may be screwed onto a thread of the transmission shaft, which isaxially fixed but rotationally connected to a threaded sleeve, which isscrewed via an external thread molded on its axial extension into asleeve having internal thread, which is in turn welded to the jointinner part. These solutions are costly and complex, and require arelatively large number of components which must be mounted in acomplicated manner one inside another and, in addition, welding is alsonecessary in some embodiments. It also is not possible tonon-destructively detach the joint inner part and the screw-in sleeve.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a functionallyreliable, cost-effective, and simple connecting arrangement forconnecting a shaft journal, such as a transmission output, with a jointpart, such as the joint inner part of a constant velocity joint.

Another object of the invention is to provide a connecting arrangementwhich can be assembled and/or disassembled in a simple manner.

These and other objects are achieved in accordance with the presentinvention as described and claimed hereinafter.

Accordingly, the connecting arrangement between a shaft journal mountedso it is axially fixed in relation to an assembly, such as atransmission in particular, and a joint part of a drive shaft which maybe linked rotationally fixed thereon, is characterized in that a shaftnut, which may be screwed via its internal thread onto the externalthread of the shaft journal, is provided with a further thread, ontowhich a further nut may be screwed via a mating thread orcounter-thread, and an axially acting form-locking connection isprovided between this further nut and the joint part which may beconnected in a rotationally fixed manner to the shaft journal.

After assembly of the transmission, the shaft nut is screwed using itsinternal thread onto the external thread of the transmission shaftjournal, until an axially oriented projection of the shaft nut contactsthe inner ring of a roller bearing. In this state, faultless and simplenoise testing and also balancing may be performed without any problems.

After the transmission has been installed in the vehicle, the driveshaft, such as the universal shaft including the joint, is installed, inparticular having a constant-velocity fixed joint, with the jointexternal part connected in rotationally fixed manner to the universalshaft, which is pushed over the joint inner part with its longitudinalteeth engaging the longitudinal teeth of the transmission shaft journal.The further nut, which is retained on the joint inner part by theaxially acting form-locking connection and yet is still rotatable, isscrewed via its thread onto the counter-thread of the shaft nut so thatthe joint inner part is tightened further on the spline teeth via theaxially acting form-locking connection, until the joint inner partcontacts and is clamped against a centering shoulder on the transmissionshaft journal.

The shaft nut may be constructed in such a way that the further threadfor the counter-thread of the further nut is an external thread.However, alternatively, the external thread may be provided on thefurther nut and a corresponding internal thread may be provided on theshaft nut.

The axially acting form-locking connection between the further nut andthe joint part, for example, the joint inner part of a constant-velocityjoint, may be a detachable connection which advantageously may be formedby a snap connection. Alternatively it may be an unlockable connection,a bayonet-type connection, a catch connection or any other type oflatchable connection.

However, the form-locking connection may also be produced by a threadprovided on the joint inner part and a counter-thread provided on thefurther nut. It may be especially advantageous if the thread on thejoint inner part and its counter-thread on the further nut have adifferent pitch direction than the thread on the shaft nut and itscounter-thread on the further nut, so that by rotation in one direction,the further nut is screwed onto the shaft nut and the joint inner partis simultaneously tightened further against the shaft journal.

Upon detachment, the connection between further nut and shaft nut isreleased by rotation in the other direction, and likewise the connectionbetween the further nut and the joint inner part, and the joint innerpart is then pushed off the longitudinal teeth of the shaft journal.With the screwing movement, i.e., with the rotation of the further nut,a greater axial path is traversed by the joint inner part relative tothe shaft journal under the force of the shaft nut than the path of thefurther nut on the shaft nut.

The thread on the joint inner part and its counter-thread on the furthernut may, however, also have a different pitch than the further thread onthe shaft nut and its counter-thread on the further nut.

It is advantageous to provide a seal between the shaft nut and thefurther nut.

Furthermore, it is advantageous if a seal is provided between thefurther nut and the shaft internal part. It is especially advantageousif the seal is axially biased against the further nut, i.e., is pressedagainst the further nut under axial pre-tension.

Furthermore, it may be advantageous if this further seal is radiallybiased, i.e., presses under radial pre-tension, for example, against ashoulder protruding in the axial direction from the further nut.

An especially advantageous embodiment results if the seal providedbetween the further nut and the joint inner part is constructed in onepiece with a seal which exerts a sealing function between joint innerpart and joint external part and thereby seals the joint.

As already noted, it is advantageous if the form-locking connectionbetween the further nut and the joint part is a detachable connection,which may be produced in an especially simple way in that a radiallyinwardly protruding collar on the further nut engages behind a radiallyoutwardly protruding bead or shoulder on the joint part, with one of thecontours, i.e., shoulder or collar, having the form of a circular ring,and the other contour, i.e. collar or shoulder, having an oval form,whose shorter axis is less than the diameter of the contour formed as acircular ring, and the areas of the elliptically formed contourassociated with the longer axis projecting radially into a groovedrecess of the other part. Such a connection may be formed in a simpleway by latching and detached by unlatching.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in further detail hereinafter withreference to illustrative preferred embodiments shown in theaccompanying drawing figures, in which:

FIG. 1 shows a connecting arrangement in the disassembled state;

FIG. 2 shows the connecting arrangement of FIG. 1 in the assembledstate;

FIG. 3 shows an embodiment of the connecting arrangement of theinventment;

FIG. 4 shows a further embodiment of the connecting arrangement of theinvention;

FIG. 5 shows an even further embodiment of the connecting arrangement ofthe invention;

FIG. 6A is a part-sectional view of an end of the shaft joint portion ofthe connecting arrangement; and

FIG. 6B is a view showing overlap of certain areas of the structureshown in FIG. 6A.

DETAILED DESCRIPTION OF EMBODIMENTS

As can be seen from FIG. 1, a shaft journal 2 mounted in a bearing 1projects out of a transmission G, which is only partially shown but iscompletely assembled. The shaft journal 2 has longitudinal teeth 3 and asection having an external thread 4. A shaft nut 5 is screwed onto thisexternal thread 4 using its counter-thread 6, which is constructed as aninternal thread, and clamped against the inner ring 1 a of the bearing.An external thread 8 is provided on an axial projection 7.

A shaft of a universal joint or Cardan joint GW has a constant-velocityjoint fixed to its end facing the transmission. The inner part 10 of theconstant velocity joint has longitudinal counter teeth 11 which matewith the longitudinal teeth 3 of the shaft journal.

A further nut 12 is fixed on the joint inner part 10 via an interlockingor form-locking connection 13, which acts in the axial direction. Toproduce this connection, the joint inner part has a groove-shaped recess14, which is delimited in one axial direction by a radially outwardlyprotruding bead or shoulder 15 and in the other axial direction by astop 16. The further nut 12 also has an internal thread 21 constructedas the counter-thread to the external thread 8 of the shaft nut 5.

The further nut 12 also has a groove 17 and a radially inwardlyprotruding collar 18. In the present illustrative embodiment, theshoulder 15 has an oval or elliptical construction and has areas 19,which extend on both sides of the longer axis of the elliptical shape ofthe shoulder 15, and which overlap with areas of the circular collar 18.The areas 20, which are associated with the shorter axis of theelliptical shape of the shoulder 15, are smaller than the diameter ofthe collar 18, so that it is possible to thread, i.e., tilt in orinsert, the shoulder 15 past the collar 18 of the further nut 12. Theoval or elliptical construction and the areas of overlap are shown inFIGS. 6A and 6B.

To attach the joint shaft GW to the shaft journal 2 and produce arotationally-fixed connection between joint inner part 10 and the shaftjournal 2 via the longitudinal teeth 3, 11, the joint shaft is firstpushed axially onto the shaft journal 2 with the teeth 11 of the jointinner part 10 engaging the teeth 3 of the shaft journal 2 until theinternal thread 21 of the further nut 12 abuts the thread 8 of the shaftnut 5. Then by rotating the nut 12, the joint inner part 10 is axiallytightened against the shaft journal 2 by the engagement between thecollar 18 and the areas 19 of shoulder 15 until the joint inner part 10engages a centering region 22 on shaft journal 2. This situation isdepicted in FIG. 2.

FIG. 2 shows the shaft nut 5, which is screwed onto the external thread4 via its internal thread 6, and on whose external thread 8 the furthernut 12 is tightened via its internal thread 21. It can thereby be seenthat the joint inner part 10 is clamped against the centering shoulder22 via the collar 18 and the areas 19.

A sealing ring 23 is provided between shaft nut 5 and the further nut12. Another seal 24, which is fastened on the joint inner part 10,contacts the further nut under axial pre-tension and presses against ashoulder 25 of the further nut 12 under axial pre-tension. In thepresent illustrative embodiment, the seal 24 is constructed in one piecewith a seal 26 which acts between joint outer part 27 and joint innerpart 10.

As previously noted, in the present illustrative embodiment the jointinner part 10 is provided with a shoulder 15, which has an oval and/orellipsoidal construction and comprises areas 19 arranged in the vicinityof the longer axis and areas 20 arranged in the vicinity of the shorteraxis.

The arrangement may also be reversed, in that the collar 18 may have anoval construction and the bead or shoulder 15 have a circularconfiguration.

FIG. 3 again shows the connecting arrangement having a shaft nut 5seated via its thread 6 on the thread 4 of the shaft journal 2, andfurthermore, a further nut 12 screwed via its internal thread 21 ontothe external thread 8 of the shaft journal. The collar 18 of further nut12 pulls the shoulder 15 (i.e., the protruding oval areas 19 thereof) ofthe joint inner part 10 against the centering region 22 of the shaftjournal 2. The form-locking, connection 13A differs from that of FIGS. 1and 2 in that in FIG. 3, the second contour, between which the collar 18is axially clamped, is formed by a snap ring 29 provided in a groove 28,via which the pulling off or pushing on of the joint shaft GW may takeplace.

In FIG. 4, a shaft nut 30 is also tightened using its internal thread 31on the external thread 4 of the shaft journal 2 and clamped against theinner ring 1 a of a roller bearing 1.

The shaft nut 30 has a further internal thread 32, into which a furthernut 33 is screwed via its external thread 34. As in FIGS. 1 and 2, theform-locking connection 13, which acts in both axial directions, isproduced in this case by a collar 18 which engages in a grooved recess14 in the joint inner part. The groove is delimited by two cantilevers19 of the oval-shaped shoulder 15, as in FIGS. 1 and 2. The stop contour16 is in turn provided on the joint inner part 10 on the side of thecollar 18 facing away from the shaft nut 30. A seal 23 is providedbetween shaft nut 30 and the further nut 33. In the same way as in FIGS.1 and 2, a seal 26, which seals the joint inner part to the joint outerpart, is also constructed in FIG. 4 in one piece with a further seal 24,which seals the joint inner part to the further nut 33.

FIG. 5 shows the shaft nut 5 screwed onto the shaft journal 2 via theconnecting threads 4, 6, and the further nut 36 screwed via its internalthread 35 onto the thread 8. The nut 36 has an internal thread 37 on theside opposite from thread 35, using which it is screwed onto thecounter-thread 38, which is arranged on the joint inner part 10. Thethreads 8, 35 have an opposite pitch direction compared to the threads37, 38. They may also have different pitches, whereby the threads 37, 38can be constructed with a steeper pitch than the threads 8, 35, so thatit is ensured that the thread turns 37, 38 are always used up before thefurther nut 36 contacts the shaft nut 5 and is clamped against it. Thethreads 8, 35 and 37, 38 may also have different lengths. In particular,the threads 37, 38 may be shorter in length than the threads 8, 35. Aseal 23 also ensures in this case, together with the seal 26, the seal24, and the cover, that grease provided between the longitudinal teeth 3and 11, which prevents wear arising due to micro-movements upon the loadchange at the inserted connection, cannot escape to the exterior. Thejoint arrangement can also effectively prevent contaminants from gettinginto the joint.

The foregoing description and examples have been set forth merely toillustrate the invention and are not intended to be limiting. Sincemodifications of the described embodiments incorporating the spirit andsubstance of the invention may occur to persons skilled in the art, theinvention should be construed broadly to include all variations withinthe scope of the appended claims and equivalents thereof.

1. A connecting arrangement for connecting an axially fixed shaftjournal and a pivotable joint part in a rotationally fixed manner,comprising: a shaft nut having an internal thread which is screwed ontoan external thread of the shaft journal; said shaft nut having anotherthread onto which a mating counter-thread of a further nut is screwed;and said further nut having an axially acting form-locking connection tosaid joint part; wherein said pivotable joint part is a joint inner partof a constant-velocity fixed joint; a first seal is provided betweensaid joint inner part and a joint outer part; a second seal is providedbetween the joint inner part and said further nut; and said second sealis axially biased against said further nut.
 2. A connecting forconnecting an axially fixed shaft journal and a pivotable joint part ina rotationally fixed manner, comprising: a shaft nut having an internalthread which is screwed onto an external thread of the shaft journal;said shaft nut having another thread onto which a mating counter-threadof a further nut is screwed; and said further nut having an axiallyacting form-locking connection to said joint part; wherein the axiallyacting form-locking connection of said further nut to said joint part isformed by a radially inwardly projecting collar on said further nutwhich engages behind a radially outwardly projecting shoulder on saidjoint part; one of said shoulder and collar having a circular ringconstruction; and the other having an oval construction with a shorteraxis which is smaller than the diameter of said circular ring.